Refrigerator

ABSTRACT

The present invention relates to an ice maker and a refrigerator having the same. A refrigerator may include a main body having a storage room therein; a compressor at one side of the main body, configured to compress refrigerant; a door on the main body, configured to open and close the storage room; an ice maker in the storage room; and a controller. The ice maker includes an ice tray configured to contain water; a guide unit under the ice tray forming a path for flowing cold air; an ice bucket under the guide unit, including a container having a concave center portion; and a rotation unit configured to move the ice in the ice tray to the ice bucket. The controller drives the rotation unit after the compressor has been operated for a preset time.

TECHNICAL FIELD

The present invention relates to a refrigerator.

BACKGROUND

A refrigerator is an apparatus for storing food at a low temperature. The refrigerator can be configured to store the food in a frozen or refrigerated state according to the type of food to be stored. The inside of the refrigerator is cooled down by continuously supplied cold air, and the cold air is continuously generated by the heat exchange action of a refrigerant by way of a refrigeration cycle going through the process of compression, condensation, expansion and evaporation. Since the cold air supplied to the inside of the refrigerator is evenly delivered inside the refrigerator owing to convection, the food inside the refrigerator can be stored at a desired temperature.

An ice maker may be provided in the refrigerator for the convenience of use. The ice maker may make ice by supplying cold air to water and storing a predetermined amount of ice. The ice maker may include an ice making tray for making ice, and an ice storage unit for storing the ice made by the ice making tray.

SUMMARY

An object of the present invention to provide a refrigerator which can effectively make ice.

Another object of the present invention to provide a refrigerator which can prevent initiating an ice removing operation in a super-cooling state.

In accordance with an aspect of the present invention, there is provided a refrigerator comprising a main body having a storage room therein; a compressor at one side of the main body, configured to compress refrigerant; a door on the main body, configured to open and close the storage room; an ice maker in the storage room; and a controller, wherein the ice maker includes an ice tray configured to contain water; a guide unit under the ice tray, forming a path for flowing cold air; an ice bucket under the guide unit and comprising a container having a concave center portion; and a rotation unit configured to move the ice in the ice tray to the ice bucket, wherein the controller drives the rotation unit after the compressor has been operated for a preset time.

The preset time may be from 30 to 60 minutes.

The ice maker may further include a temperature sensor configured to sense a temperature of the water in the ice tray, and the controller may drive the rotation unit after the preset time elapses and the temperature of the water in the ice tray is lower than an ice removing start temperature.

The ice removing start temperature may be lower than 0° C.

The ice removing start temperature is set to −5 to −13° C.

In accordance with another aspect of the present invention, there is provided a refrigerator comprising a main body having a storage room therein; a compressor at one side of the main body, configured to compress refrigerant; a door on the main body, configured to open and close the storage room; an ice maker in the storage room; a valve in a water supply pipe configured to supply water to the ice maker; and a controller, wherein the ice maker includes an ice tray configured to contain the water; a guide unit under the ice tray, forming a path for flowing cold air; an ice bucket under the guide unit and comprising a container having a concave center portion; a temperature sensor configured to sense a temperature of the water in the ice tray; and a rotation unit configured to move the ice in the ice tray to the ice bucket, wherein the controller drives the rotation unit when (i) the compressor has operated from a time of opening the valve to a preset time and (ii) the temperature of the water in the ice tray is lower than an ice removing start temperature.

When the temperature of the water is lower than the ice removing start temperature, the controller determines whether a time that the compressor has operated (e.g., after opening the valve) has reached the preset time.

The preset time may be from 30 to 60 minutes.

According to one or more embodiments of the present invention, a refrigerator which can effectively make ice can be provided.

In addition, a refrigerator which can prevent initiating an ice removing operation in a super-cooling state can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an exemplary refrigerator according to one or more embodiments of the present invention;

FIG. 2 is a rear elevation view showing an exemplary duct in the refrigerator of FIG. 1;

FIG. 3 is a perspective view showing an exemplary ice maker suitable for the refrigerator of FIG. 1;

FIG. 4 is an exploded perspective view showing the ice maker of FIG. 3;

FIG. 5 is a side cross-sectional view of the ice maker of FIG. 3;

FIG. 6 is a graph showing the change of temperature of water or ice in an ice maker according to embodiments of the present invention;

FIG. 7 is a block diagram showing control relationships in the refrigerator of FIG. 1; and

FIG. 8 is a flowchart illustrating an exemplary method of determining whether an ice maker is ready to transfer ice and/or transferring ice from the ice maker.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The disclosed embodiments may be modified in a variety of forms, and the scope of the present invention should not be limited to the embodiments described below. The embodiments are provided to explain the present invention to those skilled in the art. Accordingly, the shapes of the elements in the drawing may be exaggerated to emphasize more clear descriptions.

FIG. 1 is a perspective view showing a refrigerator according to one or more embodiments of the present invention.

Referring to FIG. 1, a refrigerator 1 according to one or more embodiments of the present invention may include a main body 10 and one or more doors 20.

Hereinafter, the direction from the rear side to the front side of the refrigerator 1 is referred to as a thickness direction, the direction from one side surface to another side surface of the refrigerator 1 is referred to as a width direction, and the direction from the bottom surface to the top surface of the refrigerator 1 is referred to as a height direction. The door(s) 20 are at the front of the refrigerator 1, and the icemaker 30 is adjacent to the top surface of the refrigerator 1.

The main body 10 provides and/or defines the overall external shape of the refrigerator 1. At least one storage room 11 may be inside the main body 10. The storage room(s) 11 inside the main body 10 may be partitioned by a barrier 12. The storage room(s) 11 may include a refrigeration room R and a freezer room F. For example, the refrigeration room R may be at or in the upper part of the main body 10, and the freezer room F may be at or in the lower part of the main body 10.

At least one door 20 is on the main body 10. The door 20 opens and closes the storage room 11. For example, the door 20 is hingedly or pivotally fixed to the main body 10 to rotate, and may open and close the storage room 11 as it rotates with respect to the main body 10. The number of doors 20 may correspond to the number of partitions of the storage room 11. For example, doors 20 are provided in front of the refrigeration room(s) R and the freezer room(s) F, respectively, and may individually open and close a corresponding one of the refrigeration room(s) R and the freezer room(s) F. For example, two doors 20 may be provided in the refrigeration room R on the left and right sides of the refrigerator 1. One or more shelves 21 may be provided on the inside surface of the door 20.

An ice maker 30 may be at or on one side of one storage room 11. For example, the ice maker 30 may be in one refrigeration room R and/or at the upper part of one of the storage rooms 11. Alternatively, the ice maker 30 may be in one door 20 or in the freezer room F.

FIG. 2 is a rear elevation view showing an exemplary duct in the refrigerator 1 of FIG. 1.

Referring to FIG. 2, a duct 40 that provides a path for flowing air may be provided in the refrigerator 1.

The duct 40 may include a cold air duct 41 and a collection duct 45.

The cold air duct 41 provides a path for supplying cold air from the space around the evaporator (not shown) to other areas of the refrigerator 1. The evaporator may be located in or behind the freezer room F, and an end of the cold air duct 45 may be connected to the freezer room F. For example, the evaporator may be adjacent to the rear side of the freezer room F, and an end (hereinafter, a supply terminal) of the cold air duct 45 may be provided to be connected to the rear side of the freezer room F.

The cold air duct 41 may include a first cold air duct 42 and a second cold air duct 43.

The first cold air duct 42 and the second cold air duct 43 may be branched at the supply terminal (e.g., at or near the fan 44) or at a point spaced apart from the supply terminal by a preset distance. The first cold air duct 42 is connected to the ice maker 30 and may supply cold air from the supply terminal to the ice maker 30. The second cold air duct 43 is connected to the refrigeration room R and may supply cold air from the supply terminal to the refrigeration room R. A fan 44 may be at a point or location in the cold air duct 41. The fan 44 may provide pressure for flowing the cold air through the cold air ducts 42 and 43 from the supply terminal. For example, the fan 44 may be located at the supply terminal (e.g., adjacent to the evaporator).

The collection duct 45 provides a path for collecting air (e.g., cold air) from other areas of the refrigerator 1 to the evaporator or the vicinity of the evaporator. The collection duct 45 may include a first collection duct 46 and a second collection duct 47. First and second ends of the first collection duct 46 may be connected to the ice maker 30 and the freezer room F, respectively. The first collection duct 46 provides a path for returning the cold air from the ice maker 30 that was used for making ice. First and second ends of the second collection duct 47 may be connected to the refrigeration room R and the freezer room F, respectively. The second collection duct 47 returns the cold air in the refrigeration room R to the freezer room F or the evaporator behind the freezer room F in response to the cold air being supplied from the evaporator (or, alternatively, the freezer room F) to the refrigeration room R.

FIG. 3 is a perspective view showing an ice maker suitable for the refrigerator 1 of FIG. 1, FIG. 4 is an exploded perspective view showing the ice maker of FIG. 3, and FIG. 5 is a side cross-sectional view of the ice maker of FIG. 3.

Referring to FIGS. 3 to 5, the ice maker may include a case 100, an ice making assembly 200, an ice bucket 300, a discharge unit 400 and a transfer unit 500.

The ice maker 30 may make and store ice.

Hereinafter, the direction from a cold air duct 110 to the discharge unit 400 is referred to as a first direction X, a direction perpendicular to the first direction X (e.g., a horizontal direction and/or in a plane) is referred to as a second direction Y, and the vertical direction perpendicular to both the first direction X and the second direction Y is referred to as a third direction Z. In addition, a side on which the discharge unit 400 is located is referred to as a front side, and a side on which the cold air duct 110 is located is referred to as a rear side.

The external shape of the ice maker 30 may be defined in part by the case 100. The case 100 may have a preset volume and a space for accommodating constitutional components of the ice maker 30 therein. The case 10 may be fixed at a point inside the storage room 11 or inside the door 20.

The ice making assembly 200 may make ice by exchanging heat of or in the water with cold air (e.g., from the duct 42). The ice making assembly 200 may include an ice tray 2100, a guide unit 2200, a rotation unit 2300 and a cover unit 2400.

The ice tray 2100 is configured to contain water. The water in the ice tray 2100 is solidified (e.g., becomes ice) through heat exchange with cold air. The ice tray 2100 may comprise a container having a center portion that is concave downwards (e.g., U-shaped), and a space and/or preset volume for containing water may be on or in the ice tray 2100. For example, the ice tray 2100 may comprise a multi-compartment container, each compartment being configured to hold a predetermined volume of liquid water and optionally having a convex lower surface, in which the center of each compartment has a greater depth than along the sidewalls of each compartment. The ice tray 2100 may have a preset length along the first direction X and a preset width in the second direction Y. For example, the ice tray 2100 may be rectangular as seen from the top (e.g., in a plan view).

A heater 2110 may be under the ice tray 2100. The heater 2110 may contact the bottom surface of the ice tray 2100 at least at one point. When the ice made in the ice tray 2100 is transferred to the ice bucket 300 by the rotation unit 2300, the heater 2110 may heat the bottom surface of the ice tray 2100 so that the ice may be effectively separated from the ice tray 2100.

The guide unit 2200 may be under the ice tray 2100. The guide unit 2200 forms a path for flowing cold air onto and/or around the ice tray 2100. The cold air flowing between the guide unit 2200 and the ice tray 2100 cools down the ice tray 2100 to freeze the water in the ice tray 2100. The guide unit 2200 may have a preset length in the first direction X and a preset width in the second direction Y. The guide unit 2200 may contact the ice tray 2100 at least at a point and may support the ice tray 2100. The rear end of the guide unit 2200 in the first direction X may communicate with the cold air duct 110 which supplies the cold air. The guide unit 2200 may be fixed to the inside surface of the case 100 or to the cold air duct 110.

The rotation unit 2300 moves the ice in the ice tray 2100 to the ice bucket 300. The rotation unit 2300 may include an ice removing shaft 2310 and a drive housing 2320.

As the ice removing shaft 2310 rotates, the ice in the ice tray 2100 is moved to the outside of the ice tray 2100. The ice removing shaft 2310 has a preset length and may be in a space above the ice tray 2100. The length of the ice removing shaft 2310 may be in or along the first direction X. One or more ice removing prominences 2311 may be along the ice removing shaft 2310. The ice removing prominence(s) 2311 may extend from the outer surface of the ice removing shaft 2310 by a preset length. The ice removing prominence(s) 2311 may not contact the water in the ice tray 2100 when the rotation unit 2300 is in a standby state (i.e., not in an operational state). When the ice removing shaft 2310 rotates for transfer of the ice, the ice removing prominence(s) 2311 may push the ice out of the ice tray 2100.

A drive unit (e.g., motor) inside the drive housing 2320 provides power for rotating the ice removing shaft 2310. The drive housing 2320 may be located at one side of the ice tray 2100 along or with respect to the first direction X. The drive housing 2320 may be located on the opposite side of the ice removing shaft 2310 from the cold air duct 110. One end of the ice removing shaft 2310 may be inserted into the drive housing 2320 by a preset length and connected to the driving unit (e.g., motor) inside the drive housing 2320.

The cover unit 2400 may be on or over the ice tray 2100, in or along the third direction Z. The cover unit 2400 may cover all or part of the ice tray 2100. The cover unit 2400 may have a preset length in the first direction X and a preset width in the second direction Y. The width of the cover unit 2400 may correspond to the width of the guide unit 2200, or may be larger than the width of the guide unit 2200 by a set width. Accordingly, the ice tray 2100 may be between the cold air guide unit 2200 and the cover unit 2400. The front end of the cover unit 2400 may contact the top of the drive housing 2320. The cover unit 2400 may be fixed to the inner surface of the case 2410 at least at one point.

A water supply unit 2410 may be at the rear end of the cover unit 2400. The water supply unit 2410 supplies water from an external source to the ice tray 2100. For example, a water supply hole 120 connected to a water supply pipe 121 may be at one side of the case 100. In addition, the water supply unit 2410 may be aligned with the water supply hole 120, and the water flowing through the water supply hole 120 may be supplied to the water supply unit 2410.

The ice bucket 300 is located under the ice making assembly 200 and contains ice from the ice making assembly 200. The ice bucket 300 may have a preset length along the first direction X and a preset width in the second direction Y. The ice bucket 300 may comprise a container, having a center portion that is concave downwards (e.g., U-shaped), and the ice bucket 300 may include a preset volume for containing ice. As seen from the top along the third direction Z, at least part of the ice bucket 300 is positioned outside the ice tray 2100 in the width direction, and the ice supplied from the ice tray 2100 may be contained in the ice bucket 300.

The discharge unit 400 may be at an end of the ice bucket 300. The discharge unit 400 discharges the ice in the ice bucket 300 to the outside of the ice maker 30 (e.g., through the corresponding door 20; see FIG. 1). The discharge unit 400 may be coupled or connected to the front end of the ice bucket 300. The discharge unit 400 may be outside the case 100. The discharge unit 400 has a width corresponding to the case 100 in the second direction Y and a height corresponding to the case 100 in the third direction Z and may shield the case 100. The discharge unit 400 may be detachable from the case 100. Accordingly, if the user separates the discharge unit 400 from the case 100 and moves the discharge unit 400 forward (e.g., out of the corresponding storage space), the ice bucket 300 may be exposed to the outside of the case 100.

The transfer unit 500 moves the ice in the ice bucket 300 to the discharge unit 400. The transfer unit 500 includes a transfer shaft 510 and a transfer housing 520.

As the transfer shaft 510 rotates, the ice in the ice bucket 300 moves to the discharge unit 400. The transfer shaft 510 has a preset length and may be in the lower part or portion the ice bucket 300. The transfer shaft 510 may have a length or rotational axis in or along the first direction X. For example, the transfer shaft 510 may be or comprise an auger.

The transfer housing 520 houses a motor that provides power for rotating the transfer shaft 510. The transfer housing 520 may be at one side of the ice bucket 300 in or along the first direction X. The transfer housing 520 may be located on the opposite side of the ice bucket 300 from the discharge unit 400. The transfer shaft 510 is coupled or connected to the transfer housing 520 or the motor therein, and may rotate by the power provided by the motor in the transfer housing 520.

FIG. 6 is a graph showing the change in the temperature of the water or ice in the exemplary ice maker.

The graph showing the change in the temperature of the water in the ice maker may be divided into an ice transfer section or period S1, a water supply section or period S2, and an ice making section or period S3.

If the temperature reaches an ice removing start temperature T1 after water is supplied to the ice tray, the ice transfer section or period Si may begin. The ice removing start temperature T1 is less than 0° C., and may be from −5° C. to −20° C. When the ice transfer section or period S1 begins, the heater 2110 begins to operate, and the ice can be effectively separated from the ice tray 2100. In addition, after a preset time has elapsed (e.g., after the beginning of the heater 2110 operation), the rotation unit 2300 operates, and the ice is moved to the ice bucket.

When transfer of the ice the ice bucket is completed, water for making ice is supplied to the ice tray in the water supply section or period S2.

When supply of water is completed, the water in the ice tray 2100 is cooled down by cold air (e.g., from the cold air duct 42) and ice is made in the ice making section or period S3. Then, when the preset temperature for removing ice is reached during the cooling, the ice transfer section or period S1 may begin again.

Such an operation of the ice maker is performed on the assumption that ice is in the ice tray 2100 at the ice removing start temperature T1. However, in the process of operating the ice maker, there may be a super-cooling section or period S4 based on a super-cooling phenomenon, in which ice is not formed in the ice tray 2100 even after the temperature of the water in the ice tray 2100 drops below 0° C., and the water in the ice tray 2100 remains in the liquid phase.

FIG. 7 is a block diagram showing control relationships in the refrigerator of FIG. 1.

Referring to FIG. 7, the refrigerator 1 may include a controller 50. The controller 50 controls constitutional components of the refrigerator 1, such as the compressor 60, the valve 150, and the like.

The ice maker 30 may include a temperature sensor 140. The temperature sensor 140 may sense a temperature of the water or the ice in the ice tray 2100. For example, the temperature sensor 140 is in the ice tray 2100 and may sense temperature of the water or the ice in the ice tray 2100. In addition, the temperature sensor 140 may be or comprise a non-contact type temperature sensor capable of sensing the temperature of a material or substance using a non-contact method, based on laser irradiation, irradiating the material or substance with infrared light, or the like. In other configurations of the ice maker 30, the temperature sensor 140 may be inside the drive housing 2320, the cover unit 2400, the cold air guide unit 2200, the ice bucket 300, or the case 100, and may sense the temperature of the water or the ice in the ice tray 2100.

The valve 150 is in a path for supplying water to the ice maker 30 and opens and closes the path for supplying water to the ice maker 30. For example, the valve 150 may be at a point or location in the water supply pipe 121.

The compressor 60 is at one side of the main body 10. The compressor 60 is connected to the evaporator and is part of a path for circulating refrigerant in the refrigerator 1. After heat-exchange in the evaporator, the refrigerant flows into the compressor 60. The refrigerant absorbs ambient heat when it evaporates inside the evaporator, and may flow to the compressor 60 in a gas state and/or in a liquid state. The compressor 60 may compress the refrigerant and supply the compressed refrigerant back to the evaporator. The refrigerant supplied to the evaporator may be condensed into a liquid in the process of compression and/or being returned to the evaporator.

The controller 50 controls constitutional components of the refrigerator 1. For example, the controller 50 has one physical configuration at one side of the refrigerator 1 to control the ice maker 30, a valve 150, the compressor 60 and other constitutional components of the refrigerator 1. Alternatively, the controller 50 may have two or more physical configurations, and they may be at one or more points or locations in the refrigerator 1. In addition, part of the controller 50 may control the ice maker 30, and other part(s) of the controller 50 may control other constitutional components of the refrigerator 1. When the controller 50 has two or more physical configurations, each part of the controller is electrically connected to the other part(s), and may perform control in connection and/or cooperation with each other.

FIG. 8 is a flowchart illustrating an exemplary method of determining whether an ice maker is ready to transfer ice and/or transferring ice from the ice maker.

Referring to FIG. 8, the controller 50 determines whether the operation time of the compressor 60 is longer than a preset time (step S100). The operation time of the compressor 60 may be calculated from the time point of opening the valve 150 and supplying water to the ice maker 30. The operation of the compressor 60 may be performed intermittently. For example, the controller 50 may stop the operation of the compressor 60 when the temperature of the storage room 11 is lower than a preset temperature and may operate the compressor 60 when the temperature of the storage room 11 is higher than the preset temperature. Accordingly, the controller 50 determines whether a preset time has elapsed after the compressor 60 begins to operate and/or after the valve 150 is opened and water is supplied to the ice maker 30. For example, the preset time may be 30 to 60 minutes.

The controller 50 determines whether the temperature of the water sensed by the temperature sensor 140 is lower than an ice removing start temperature T1 (step S200). When the temperature of the water 140 is lower than the ice removing start temperature T1, the controller 50 controls the rotation unit 2300 of the ice maker to transfer ice from the ice tray 2100 to the ice bucket 300 (step S300). The ice removing start temperature T1 may be less than 0° C. For example, the ice removing start temperature T1 may be −5 to −13° C.

In another embodiment, the controller 50 may determine first whether the temperature of the water 140 is lower than the ice removing start temperature T1, and then determine whether the operation time of the compressor 60 (e.g., after the water is supplied through the valve 150) is longer than the preset time.

In still another embodiment, when the operation time of the compressor 60 after initiating the supply of water is longer than the preset time, the controller 50 may omit determining the temperature of the water (e.g., as sensed by the temperature sensor 140) and begin the ice removing operation.

The super-cooling section or period S4 may occur during the ice making section or period S3, and the ice removing start temperature T1 may be reached while the water is in the super-cooled state. When the controller 50 controls the rotation unit 2300 so that the rotation unit 2300 begins the ice removing operation on the basis of reaching the ice removing start temperature T1, the ice removing operation may be performed while the water in the ice tray is in the super-cooled (and thus liquid) state. Accordingly, although the ice removing operation is performed, neither the water nor ice is removed from the ice tray 2100. If additional water is supplied to the ice maker 30 in this state, the ice is not made in a desired state in the ice maker 30. For example, excess water in the ice tray 2100 can spill over into the ice bucket 300 and freeze in the ice bucket 300, which can disrupt operation and/or damage of the ice maker 30.

In addition, it may not be possible to prevent the ice removing operation from being performed during the super-cooling section or period S4, even though the ice making section or period S3 is over. The time of the ice making section or period S3 after water is supplied to the ice tray 2100 may vary according to the operation or operational state of the refrigerator 1. Specifically, when the supply of cold air to the ice maker 30 increases, the time for solidifying water (e.g., making ice) is reduced, and when the supply of cold air to the ice maker 30 decreases, the time of changing water to ice is increased. The amount of the cold air supplied to the ice maker 30 varies according to the operation state of the compressor 60 or the fan 44. The compressor 60 may operate when the temperature of the storage room 11 is higher than a preset temperature. In addition, the fan 44 (which may flow or otherwise move cold air from the freezer room F to the refrigeration room R and/or to the ice maker 30) may operate when the temperature of the storage room 11 is higher than the preset temperature. Accordingly, the supply of cold air to the ice maker 30 and the time of the ice making section or period S3 may vary according to conditions such as the temperature of the storage room 11, the temperature of the space in which the refrigerator 1 is located, the number of times that the door 20, and the like.

Contrarily, the refrigerator 1 according to one or more embodiments of the present invention may begin the ice removing operation depending upon and/or according to the operation time of the compressor 60 and the amount of cold air supplied to the ice maker 30, according thereto. Accordingly, initiating the ice removing operation in the super-cooling state S4 is prevented. Specifically, if the operation time of the compressor 60 elapses a preset time after the ice making section or period S3 begins and a sufficient amount of cold air has been supplied to the ice maker 30, the water passes through (or does not enter) the super-cooled state S4, and is condensed into ice even when the water is in the super-cooled state S4.

According to one or more embodiments of the present invention, a refrigerator which can effectively make ice can be provided.

In addition, a refrigerator which can prevent initiating an ice removing operation in a super-cooling state can be provided.

The above detailed description provides examples of the present invention. In addition, the above description explains by showing preferred embodiments of the present invention, and the present invention may be used in various different combinations, changes and environments. That is, the present invention may be modified or changed within the scope of the spirit of the present invention disclosed in this specification, within a scope equivalent to the disclosed contents, and/or within the scope of the technique(s) or knowledge of the prior art. The above embodiments describe the best conditions for implementing the technical spirit of the present invention, and various changes in the specific application fields and usages of the present invention also can be made. Accordingly, the detailed description of the present invention as described above shows disclosed embodiments and is not intended to limit the present invention. In addition, the appended claims should be interpreted as also including other embodiments. 

What is claimed is:
 1. A refrigerator comprising: a main body having a storage room therein; a compressor at one side of the main body, configured to compress refrigerant; a door on the main body, configured to open and close the storage room; an ice maker in the storage room; and a controller, wherein the ice maker includes: an ice tray configured to contain water; a guide unit under the ice tray, forming a path for flowing cold air; an ice bucket under the guide unit and comprising a container having a concave center portion; and a rotation unit configured to move the ice in the ice tray to the ice bucket, and the controller drives the rotation unit after the compressor has been operated for a preset time.
 2. The refrigerator according to claim 1, wherein the preset time is from 30 to 60 minutes.
 3. The refrigerator according to claim 1, wherein the ice maker further includes a temperature sensor configured to sense a temperature of the water in the ice tray.
 4. The refrigerator according to claim 1, wherein the controller drives the rotation unit after the preset time elapses and the temperature of the water in the ice tray is lower than an ice removing start temperature.
 5. The refrigerator according to claim 4, wherein the ice removing start temperature is less than 0° C.
 6. The refrigerator according to claim 4, wherein the ice removing start temperature is −5 to −13° C.
 7. A refrigerator comprising: a main body having a storage room therein; a compressor at one side of the main body, configured to compress refrigerant; a door on the main body, configured to open and close the storage room; an ice maker in the storage room; a valve in a water supply pipe, configured to supply water to the ice maker; and a controller, wherein the ice maker includes: an ice tray configured to contain the water; a guide unit under the ice tray forming a path for flowing cold air; an ice bucket under the guide unit and comprising a container having a concave center portion; a temperature sensor configured to sense a temperature of the water in the ice tray; and a rotation unit configured to move the ice in the ice tray to the ice bucket, and the controller drives the rotation unit when the compressor has operated from a time of opening the valve to a preset time and the temperature of the water in the ice tray is lower than an ice removing start temperature.
 8. The refrigerator according to claim 7, wherein when the temperature of the water in the ice tray is lower than the ice removing start temperature, the controller determines whether a time that the compressor has operated has reached the preset time.
 9. The refrigerator according to claim 7, wherein the preset time is from 30 to 60 minutes.
 10. A method of operating an ice maker in a refrigerator, comprising: guiding flowing cold air under an ice tray in the ice maker to solidify water in the ice tray to ice; operating a compressor of the refrigerator for a preset time; and driving a rotation unit in the ice maker after the compressor has been operated for a preset time to move the ice in the ice tray to the ice bucket.
 11. The method of claim 10, further comprising supplying the water to the ice tray by opening a valve in a water line of the refrigerator.
 12. The method of claim 11, wherein the preset time is a time from opening the valve to the ice in the ice tray reaching a preset temperature.
 13. The method of claim 12, further comprising sensing a temperature of the water and/or ice in the ice tray using a temperature sensor.
 14. The method of claim 12, wherein the rotation unit is driven after the temperature of the water and/or ice in the ice tray reaches the preset temperature. 